Aquacraft Lipo Grim Racer 2S 7.4V 5000Mah 40C RC Battery Designed and tested specifically for boat Hulls and boat racing Requires: LiPo compatible charger and balancer Voltage rating: 7.4V Cells: 2 Discharge rating: 40C Continuous, 80C surge max. Recommended charge Rate: 1C (5.0A) Always use a lipo-approved charger always use a LiPo Cell balancer. Always charge in a fireproof location Never: trickle charge or charge over 4.20V per Cell. Never disassemble, puncture or modify pack in any way. Never leave UNATTENDED during charging.